Channel equalization in communication systems may be used to flatten the frequency response of a communication channel such as a wire-line, an optical fiber, or a radio-frequency (RF) channel. A flat frequency response can allow a faithful reproduction of the attributes of the input signal of the communication channel at the output end of the communication channel. Many equalizers are implemented in digital, for example, by a large number of finite impulse response (FIR) de-emphasis taps (e.g., pre and post-tap drivers) to equalize channels that have long impulse response tails. These equalizer may be power hungry, inefficient, and result in a significant drop (e.g., de-emphasis) of the peak amplitude.
Amplitude equalization may be effective in opening eye diagram amplitude and to some extent in opening eye diagram width (e.g., edge equalization), but may be less effective in edge equalization and in boosting the rise/fall time of the equalizer output signal. Voltage mode drivers used in some existing equalizers may contribute to output capacitances that can significantly increase as the number of driver slices increase and can drastically impact rise and/or fall times of the driver output signals. Other existing solutions may use a low-pass filter (LPF) after a post-tap driver to generate a decaying tail that can match the impulse response of the channel with an opposite polarity. Such solutions may be adequate for current-mode logic (CML) drivers where a linear data buffer can be easily implemented.